Lubricated hook for sewing machines



Patented Sept. 8, 1942 LUBRICATED HOOK FOR SEWING MACHINES William L. Barron, Laurence Harbor, N. J., as-

signor to The Singer Manufacturing Company, Elizabeth, N. J a. corporation of New Jersey Application September 13, 1940, Serial No. 356,571

1 Claim.

This invention relates to sewing machines and more particularly to means for lubricating the rotary hook of lock-stitch sewing machines.

It has been found that when the oil is led directly to the raceway of a rotary hook by means of ports which open directly into the raceway, the lint and sizing from the material being sewn finds its way to the ports and the ports become clogged. This clogging of the ports reduces the amount of oil supplied to the raceway and, when heating occurs, the sizing and lint become more and more impervious to oil with the result that no oil at all reaches the raceway and the hook is ruined due to overheating. It is one of the objects of this invention to overcome this condition by providing a piece of wicking which completely fills at least one of the openings into the raceway so that no foreign material can collect in the opening.

Another object of this invention is to locate some of the ports which open into the raceway beneath a removable cover on the hook so that access may be readily had to these ports for the purpose of inspection and cleaning, and to reduce the cost of manufacture.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawing,

Fig. 1 is a sectional view taken through the center of a rotary hook, embodying the invention; the hook-actuating shaft and the bearing bushing in which the hook-shaft is journaled also being shown in section.

Fig. 2 is a side elevation of my improved rotary hook, the guard-plate being removed to expose the oil ports leading to the raceway.

Fig. 3 is a disassembled perspective View of my improved hook.

In the embodiment of this invention selected for illustration, l represents the bearing lug carried on the under side of the bed-plate of a lock-stitch sewing machine. Carried by the lug I0 is a bearing-bushing ll having a longitudinally arranged conduit l2 to which oil is supplied by means of a pipe I3 which is connected to a pump (not shown) actuated by the mechanism of the sewing machine. The conduit l2 to circular groove l3 to a second longitudinally arranged conduit M provided with a screw l5 which may be removed when no lubrication of the raceway for the hook is desired. The oil which is under pressure in the conduit I4 enters the longitudinal bore It in the hook-shaft I6 through the circular groove 11 in the bushing and radial duct I8 in the hook-shaft. The oil in the longitudinal bore I6 is filtered by the wick l9 and is delivered to the hook by means of the radial ducts 2| and conduits 22 formed in the radial portion 23 of the cup-shaped hookbody 24.

The above described mechanism is disclosed in the co-pending application of W. J. Peets et al., Serial No. 280,488, filed June 22, 1939, to which reference may be had for a more complete and detailed description of the means for delivering the oil under pressure from a sump in the sewing machine to the rotary hook.

Journaled in the raceway 25 of the hook-body 24 is the bearing rib 26 of the stationary threadcase 21 which is held against rotation by means of the usual Well known rotation-restraining finger. Located near the beak 24' of the hook and beneath the guard-plate 28, which is fixed to the hook-body by means of the screws 29, there is formed an elongated opening or pocket 30 which has a smaller port 3| communicating with the raceway 25 (Figs. 1 and 2). Connected with the pocket 30 is a circumferential groove 32 provided with spaced ports 33 which open to the raceway. Located in the pocket 30 is a piece of wicking 34 which is larger in diameter than the depth of the pocket 30. The wicking 34 is placed in the pocket 30 and then the guard-plate is placed in position and screwed fast to the body of the hook by the screws 29. This compresses the wicking 34 and causes a portion of it to bulge or extend out through the smaller opening 3| into the raceway 25 so that it' engages the outer periphery of the bearing rib 26. By compressing the wicking material in the pocket 30 so that the pocket 30 is completely filled, as well as the port 3|, no lint or foreign matter can now work its way into the port 3! and pocket 30 and prevent the oil from being supplied to the hook. It will be observed that the guard-plate 28 may be removed for the purpose of replacing the wicking 34 and the ports cleaned without the necessity of removing the hook from the machine. Further, the pocket 30, groove 32 and ports 3| and 33 are formed in the body of the hook at its Which oil is supplied is connected by means of a outer periphery and covered by the guard-plate 28. This construction reduces the cost of manufacture of the hook.

Having thus set forth the nature of the invention, what I claim herein is:

A sewing machine having, in combination, a horizontal rotary shaft provided with a longitudinal bore, means for supplying oil to the bore in said shaft, a rotary hook carried by said shaft and having a cup-shaped body formed with a raceway on the inner periphery of its wall and a pocket formed in the outer periphery of the wall and connected to the raceway by a radially arranged port which is smaller than the pocket and located centrally thereof, a piece of wicking in said pocket which when not compressed is larger than the pocket, a plate attached to the outer periphery of the Wall for compressing said wicking to cause a portion thereof to extend into and fill the port connecting the pocket with the raceway, and a conduit for supplying oil from the bore in the shaft to the pocket while the hook 10 is rotating. 

